Prototype

The prototyping phase enables us to test functionality of our design, we can identify any flaws or issues with our design and make necessary adjustments. By creating a physical representation of our design, we can get a better sense of how the product will look and feel and make changes accordingly. This can help ensure that the final product is both functional and aesthetically pleasing.  In order to make a good prototype it is necessary to have a clear vision of what the prototype should look like and function. By doing so, it is possible to start formulating a technical plan as well as informing the case owner of what the prototype can become.  

In the case of Lightmate it was clear from the start that the intentions were to create a fully functional prototype. This prototype would have all functions that the final product would have, which would look like and function like the final product. However, in order to do so we would require electronic components the size of coins. Hence, the final prototype has been divided into two separate prototypes: 

  1. Real size prototype: This prototype would help the user envision the dimensions of the final product as well as some functionalities; such as the magnetic closing mechanism, the hinge mechanism and finally how the product can adapt to different diameters.  
  1. Functional prototype: This prototype would communicate to the user the electronic functionalities of the product; such as the vibrating sensors, LED strip and the microcontroller. Said electronics will be integrated into a 3 casing which will resemble the final product. This casing will also present some of the mechanical features of the product such as the closing mechanism and the hinge.  

Real-life size prototype

How did we figure out the dimensions? How did we take the requirements into consideration? 

The dimensions were decided by the co-designer, who specified that his cane has a diameter of approximately 12 mm (about 0.47 in) and his dog leash has a diameter of 24 mm (about 0.94 in). According to the requirements the light should be multifunctional, which means the light is capable of attaching to different objects that help him with walking in the dark. To accommodate these requirements, we chose a range of 10 mm to 30 mm for adjusting the prototype. Using a spring system, we made the inner diameter of the body 30 mm and the length of the spring block 17 mm (including 2 mm of overlap). Considering the weight of the product, we determined that a minimum height of 28 mm was needed to compact all the components. 

Material selections? What parts does the prototype have?

Regarding material selection and the prototype’s parts, we decided to use plywood as the main material. It was the most straightforward way to achieve the spring mechanism and hinge by using layers. We laser-cut the plywood with a thickness of 4mm and used wood glue to connect seven layers to reach a height of 28 mm. For the spring mechanism’s size, we used a diameter of 8mm to select the spring. 

What process did we go through to get to the final prototype? 

We laser-cut the plywood into 14 pieces (left half:part6 4x, part5 2x, part 2 1x, part 1 1x, right half: part 3 4x, part7 2x, part4 1x, part1 1x).  

Final (real-life size) prototype

Functional prototype

Electronics

The process of creating a functional prototype would require the team to use electronic components that are cheap and easily obtained and fulfil all the functions that the product should have. These components should also be of small size so a CAD model can be made where these components can be housed.  

The components that are needed are a on/off switch, a haptic/vibration motor, a battery, and a lightstrip. To make sure these components can connect properly to each other, the team used an Arduino Nano. This is a small microcontroller which can connect to multiple hardware components and control them using software functionality. This makes the prototyping phase much more convenient because the team can make easy changes through software changes without costing too much time, which helps for testing and improving.  

The usage of an Arduino Nano meant that the prototype required an input voltage of at least 5V for the microcontroller to be powered properly, as well as a sufficient current supply which has a long-lasting power supply. The option of a rechargeable battery was ditched because the system would not have a high current draw. Therefore, using an interchangeable Alkaline battery is much more convenient because an Alkaline battery works better with systems which have low current draw, so it would be able to power the prototype for a potentially months. The option was considered to use 3 or 4 AAA batteries which would be connected in series to get the desired output voltage. This would be a good option which is also widely used in other products such as flashlights, however, it would be much easier to use a single 9V battery 

List of Electronic components: 

Part NameVoltage (Output/Input)
Arduino Nano>>5V (Input)
Vibration Motor5V (Input)
LED strip5V (Input)
On-Off switch
Panasonic 9V battery9V (Output)
Table of electronic components

CAD model

Creating a CAD model will ensure a more precise measurement of dimensions as well as fittings for the electronic components. As stated, the functional prototype will have electronic functionalities and some mechanical functionalities.

While deciding how to make the case, the following questions were asked:

  • How will the casing be made?
  • What material will the casing be made of?
  • What dimensions will the casing have?
  • How many parts will the casing have?
  • How are the electronic components will be integrated into the casing?

Answering all these questions is the key to making a good-quality prototype. And thus, we assessed each question individually keeping in mind the requirements of this project.

How will the casing be made?

Considering the complexity and the diversity of the electronic components, unprecise methods of prototyping were eliminated such as foam-shaping. With laser cutting and 3D printing being the only viable options, it’s sensible to deduce that laser cutting would entail that the product should be constructed by layers, making the whole process tedious and unnecessarily long. Therefore, 3D printing was the best option thanks to its precise machining and fast delivery results.

What material will the casing be made of?

Since the casing of the prototype will be made through 3D printing, material options are limited. Consequently, a short talk with the Design LAB team was done to ensure that the 3D printing material would have the necessary properties for the final design. After some tests, it was concluded that the material showed good results and would be sufficient to produce the prototype.

What dimensions will the casing have?

Determining dimensions was quite a challenge at first since the goal is to keep it as compact as possible, which would help the user imagine the real-life product. It was in the interest of the group to keep the inner diameter of the casing the same as the final product. Several variables were considered while determining the outer diameter and the thickness of the prototype: the size of electronic components, the size of screws, the size of magnets, and general ergonomic principles.

How many parts will the casing have? 

While brainstorming how to assemble or piece together the prototype we ran into the following obstacles:  

  • Not all electronic components (battery, microcontroller, vibration sensor, LED strip, and wires) could fit in one half of the product.  
  • There should be a removable piece to have access to the components.  
  • If all parts are 3D printed hinge mechanism cannot be put together in one piece. As well as having a lot of supports which would make the integration of components a lot harder.  

We resolved all of these problems by splitting the whole prototype into 6 different parts: 

Lids for part 1 & part 2

By doing so we can use the hinge as a wire bridge from one half to the other, allowing for the product to have components on both sides. Splitting the main body of the prototype enables the 3D printer to not have any unnecessary supports allowing the product to have an easy assembly. By having two lids, the product has the ability of opening and close, thus having access to the components and the interior of the product.  

The final functional prototype will be ready for testing on the day of the presentation.